1. Field of the Invention
The invention relates to a memory device. More particularly, the invention relates to a memory cell, a memory device and a method for manufacturing a memory cell.
2. Description of Related Art
An electrically erasable programmable read only memory (EEPROM) of a non-volatile memory has advantages of performing multiple data program, read and erase operations and maintaining stored data during power-off, it becomes a memory device widely used by personal computers and electronic equipments.
During a program process of a memory cell of the EEPROM that is performed through channel hot electrons, holes generated on a surface of a substrate due to an impact ionization can probably cause a secondary impact ionization in a direction of the substrate to generate more pairs of electrons and holes. Since sizes of the memory cells become smaller, and a source/drain doped region is shared, the generated secondary hot electrons can probably cross over the doped region and lead to a program operation to an adjacent memory cell, so that data in the adjacent memory cell is influenced, and such phenomenon is referred to as program disturbance.